ScalingStacks

Remark 4.1 . [04YM]

Original official author HTML, exact retained edition. Historical TeX conversion verdicts remain unchanged. Cited-edition alignment and mathematical self-containment are not assessed.

Complete original source context · Original author HTML

Remark 4.1.

Recall the concepts of the class of metric (metric class) and the radiance obstruction of Mongé-Ampére manifolds BB with singularities. They are introduced in [KS04] and discussed in [GS06] in more details. We denote them by k⁡(B)∈H1​(B,i∗​Λ~∨⊗ℝ)k(B)\in H^{1}(B,i_{*}\tilde{\Lambda}^{\vee}\otimes\mathbb{R}) and c⁡(B)∈H1​(B,i∗​Λ)c(B)\in H^{1}(B,i_{*}\Lambda), respectively. Here, Λ\Lambda is the affine structure as a ℤ𝑑𝑖𝑚⁡(B)\mathbb{Z}^{\it dim(B)}-local system in tangent bundle T⁡(B∖Δ)T(B\setminus\Delta), −∨-^{\vee} denotes −-’s dual local system, Λ~∨\tilde{\Lambda}^{\vee} is local system of affine functions. In particular, we naturally have a morphism of local systems f:Λ~∨→Λ∨f\colon\tilde{\Lambda}^{\vee}\to\Lambda^{\vee} which induces f∗:H1​(B,i∗​Λ~∨)→H1​(B,i∗​Λ∨)f_{*}\colon H^{1}(B,i_{*}\tilde{\Lambda}^{\vee})\to H^{1}(B,i_{*}\Lambda^{\vee}). It is also easy to see that, if we slightly change the definition of the metric class, to extract its “linear” part as f∗​k​(B)f_{*}k(B). Then, it naturally recovers the data v¯∈(e⟂⊗ℝ/ℝ​e)\overline{v}\in(e^{\perp}\otimes\mathbb{R}/\mathbb{R}e) i.e., we have f∗​k​(Φalg​([e,v]))=[v],f_{*}k(\Phi_{\rm alg}([e,v]))=[v], under the natural identification H1​(Φalg​([e,v]),i∗​Λ∨⊗ℝ)↪(e⟂⊗ℝ/ℝ​e)H^{1}(\Phi_{\rm alg}([e,v]),i_{*}\Lambda^{\vee}\otimes\mathbb{R})\hookrightarrow(e^{\perp}\otimes\mathbb{R}/\mathbb{R}e) which comes from the Leray spectral sequence applied to the elliptic fibration X↠Φalg​([e,v])X\twoheadrightarrow\Phi_{\rm alg}([e,v]) in §4.2. Our results in [Od16] and Theorem 3.1 for AgA_{g} can be re-interpretted similarly (but with weight 11).

Original mathematics by the credited authors. Source-backed reader collection; mathematical self-containment is not assessed.